The present invention relates to a compressor which discharges, into a sealed container, a refrigerant compressed in a compression mechanism portion.
Heretofore, this type of compressor, for example, a horizontally disposed multistage compression type rotary compressor including a first compression element and a second compression element has been constituted of a driving element disposed in a laterally long cylindrical sealed container, and a compression mechanism portion extended in the horizontal direction of the driving element and including the first and second compression elements which are driven around the rotary shaft of the driving element. Then, a low-pressure refrigerant gas is sucked into the low pressure chamber side of a cylinder from the suction port of the first compression element, compressed by the operations of a roller and a vane to obtain an intermediate pressure, and discharged into the sealed container from a high pressure chamber side through a discharge port and a discharge sound absorbing chamber. The refrigerant gas having the intermediate pressure and discharged into the sealed container is sucked into the low pressure chamber side of the cylinder from the suction port of the second compression element. This refrigerant gas is secondarily compressed by the operations of the roller and the vane, and becomes a high-temperature high-pressure refrigerant gas. This gas is discharged from the compressor via the high pressure chamber side through a discharge port and a discharge sound absorbing chamber.
Moreover, the bottom part of the sealed container is constituted as an oil reservoir, and oil is sucked from the oil reservoir by an oil pump as oil supply means constituted on one end of the rotary shaft, and is supplied to the compression mechanism portion via an oil passage formed in the rotary shaft, to prevent wear on the compression mechanism portion, the sliding portion of the rotary shaft or the like.
In addition, as this type of compressor, a compressor has been developed in which an ejector oil pump is attached to one end of the rotary shaft to supply the oil to the sliding portion by use of an ejector effect produced by the ejector oil pump. That is, the ejector oil pump is constituted of an oil suction pipe having one end connected to the oil passage of the rotary shaft and the other end which opens in the oil reservoir, and an ejector pipe having one end connected to the discharge side of the first compression element and the other end inserted into the opening of the other end of the oil suction pipe. The inner diameter of the other end of the oil suction pipe is larger than the outer diameter of the other end of the ejector pipe so that a gap for oil suction is constituted between both the pipes. Then, the oil of the oil reservoir is sucked into the rotary shaft from the gap for oil suction owing to the ejector effect using the intermediate-pressure refrigerant discharged from the first compression element, and the oil is supplied to the compression mechanism portion via the oil passage in the rotary shaft.
Thus, in the compressor including the first compression element as the first stage and the second compression element as the second stage, a discharge gas amount and a flow rate are determined by the displacement capacity of the second compression element as the second stage. Therefore, the change of the volume of the gas to be discharged from the first compression element is small, so that the oil can stably be supplied to the sliding portion with the ejector oil pump by use of the refrigerant gas discharged from the first compression element (e.g., see Japanese Patent Application Laid-Open No. 2005-36740).
The above conventional compressor has a constitution in which the ejector pipe is simply inserted into the oil suction pipe of the ejector oil pump, so that the dimension, inserting position and the like of the ejector pipe to be inserted into the oil suction pipe have not been defined. However, the gap for oil suction or the like becomes different in accordance with the dimension and position of the ejector pipe to be inserted into the oil suction pipe. In consequence, there has been a problem that the amount of the oil to be sucked by the ejector oil pump becomes remarkably different owing to the variable gap for oil suction or the like, the amount of the oil to be sucked by the ejector oil pump becomes unstable, and the oil cannot stably be supplied to the sliding portion.